Antiarrhythmia therapies such as pacing and defibrillation frequently involve delivery of an electric signal to the heart or to anatomy near the heart. Pacing therapies include delivery of a low-energy electrical pulse to the heart. Defibrillation therapies typically include delivery of an electrical energy signal that is strong enough to defibrillate the heart.
A pacer device typically includes a pulse generator and an electrode through which an electrical signal is delivered to the heart. A defibrillator typically includes a pulse generator and two or more electrodes through which an antitachyarrhythmia therapy is delivered. Some devices include both pacing and defibrillation capability. In an example, a medical device includes a lead assembly having at least one electrode that is positionable in, on, and/or around the heart. An antiarrhythmia therapy is delivered using the at least one electrode. In mature patients, a medical device such as a pacer or defibrillator is usually implanted in the thorax, with leads extending from the medical device and into a vein that leads into the heart. A pulse generator is frequently implanted subcutaneously, for example.
In small patients, especially in utero patients, implantation of subcutaneous devices and lead assemblies can be complicated because of the small, fragile, rapidly-growing anatomy of the patient. Improved cardiac rhythm management methods and systems for fetal, neonatal and/or pediatric patients are needed.